A PPy-AOPIM-1 / SA aerogel evaporator with vertical channels, its preparation method and application

Abstract

This invention relates to the field of aerogel evaporator technology, specifically to a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels, its preparation method, and its applications. The invention includes the following steps: S1, synthesis of PIM-1; S2, synthesis of amidine oxime PIM-1 powder; S3, preparation of PPy-modified AO-SA aerogel. The invention functionalizes PIM-1 by introducing amidine oxime groups (AO), forming AOPIM-1 with an amphoteric structure, enhancing its hydrophilicity and salt resistance. Subsequently, sodium alginate is doped to prepare a vertically oriented aerogel, PPy-AOPIM-1 / SA. Under single-day illumination, the photothermal evaporation efficiency of this aerogel evaporator in pure water and 20wt% NaCl solution reached 91.17% and 83.67%, respectively. Furthermore, PPy-AOPIM-1 / SA also performs excellently in wastewater purification, efficiently purifying dye wastewater and exhibiting superior purification performance in acid and alkaline wastewater treatment, with the pH of the evaporated solution approaching neutral.

Description

Technical Field

[0001] This invention relates to the field of aerogel evaporator technology, specifically to a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels, its preparation method, and its application. Background Technology

[0002] Solar-driven interfacial evaporation (SIE) is considered an economically effective strategy for addressing freshwater scarcity and plays a crucial role in drinking water production. However, in complex aquatic environments, factors such as high salinity, high concentrations of acids and alkalis, and heavy metal ions severely limit its widespread application. Therefore, developing interfacial evaporators adapted to complex aquatic environments remains a major challenge. Currently, SIE technology still has limitations in terms of evaporation rate and salt resistance. To improve the evaporation rate, researchers typically focus on optimizing photothermal materials, which absorb solar energy and convert it into heat to drive water evaporation. A wide variety of photothermal materials exist, including carbon materials, plasma materials, metal nanoparticles, and semiconductor materials. To address the problem of salt accumulation during evaporation, researchers have developed designs such as the Janus evaporator and porous structures to significantly reduce the impact of salt crystal accumulation on evaporation efficiency. In recent years, porous organic polymers (POPs) have become a focus of research in photothermal conversion materials due to their controllable molecular design, customized pore structure, excellent solar energy absorption performance, and low thermal conductivity. Various porous organic materials (POPs), including conjugated microporous polymers (CMPs), covalent organic frameworks (COFs), hypercrosslinked porous polymers (HCPs), intrinsically microporous polymers (PIMs), and porous ionomers (PIPs), have been developed and applied in photothermal applications such as seawater desalination, energy storage, and biomedicine. Among these, intrinsically microporous polymers (PIMs) and porous aromatic frameworks (PAFs) are widely used for the adsorption and separation of persistent organic pollutants due to their diverse structures, low density, large specific surface area, and excellent physicochemical stability. PIM-1, as an important member of the PIM series, exhibits significant application potential in gas separation and ion exchange membranes due to its unique fused ring and twisted site structure, resulting in high free volume and controllable molecular size. However, PIM-1 has some limitations in practical applications, such as limited hydrophilicity and weak salt resistance. To improve its performance, researchers functionalized PIM-1 by introducing amine oxime groups (AOs), forming AOPIM-1. This modification significantly enhances the hydrophilicity and salt resistance of PIM-1, enabling its widespread application in natural gas purification, flow batteries, and other fields. Studies have shown that the hydrophobic backbone and hydrophilic side chains of AOPIM-1 can construct interconnected water transport channels, significantly reducing the mass transport resistance of the solvent and thus improving evaporation efficiency. To broaden the application areas of self-contained microporous polymers, this invention introduces AOPIM-1 into a solar interfacial evaporation system for the first time and combines it with sodium alginate to prepare a novel PPy-AO-PIM-1 / SA aerogel evaporator. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels, its preparation method, and its application, thereby solving the problems encountered by existing technologies in complex seawater environments.

[0004] To achieve the above objectives, the following technical solution is provided:

[0005] A method for preparing a PPy-AOPIM-1 / SA aerogel evaporator with a microporous polymer combined with sodium alginate and having vertical channels, characterized by comprising the following steps:

[0006] Step 1: Synthesis of PIM-1; PIM-1 is synthesized using a low-temperature method, specifically including the following steps:

[0007] First, TTSBI was purified by recrystallization from methanol and dichloromethane and dried overnight in a vacuum oven at 80°C. TFTPN was purified by recrystallization from methanol at 60°C and quenched with potassium carbonate at 120°C before use. Under nitrogen atmosphere, 10.2 g of TTSBI, 6 g of TFTPN, and 200 mL of anhydrous DMAc were added to a three-necked round-bottom flask. The mixture was stirred and heated to 65°C to completely dissolve the monomers. After dissolving into a clear solution, 10 g of K2CO3 was introduced into the solution to make the molar ratio of TTSBI, TFTPN, and K2CO3 1:1:2.5. The reaction was carried out at 65°C under inert gas atmosphere for 72 hours. After the reaction was completed, the solution was cooled to room temperature and then poured into methanol.

[0008] The resulting precipitate was then purified by dissolving it in chloroform and further recrystallized with methanol. The resulting polymer was refluxed in distilled water overnight, then filtered and washed several times to remove residual salts.

[0009] Finally, it was dried overnight in a vacuum drying oven at 100°C to obtain PIM-1 as a yellow solid.

[0010] Step 2, synthesis of amide oxime PIM-1 powder, specifically includes the following steps:

[0011] First, add 0.6 g of PIM-1 powder and 40 mL of THF to a three-necked round-bottom flask equipped with a condenser and a magnetic stirrer, and heat the solution to 65°C and maintain it in an inert nitrogen atmosphere.

[0012] Then, using a syringe, 6 ml of hydroxylamine was added dropwise to the solution, causing the solution to become cloudy and contain some precipitate. The reaction was carried out under reflux for 20 hours.

[0013] Finally, after the reaction was complete, the turbid solution was cooled to room temperature and poured into excess methanol. AOPIM-1 was separated by filtration and washed multiple times with ethanol to obtain an off-white powder, which was then dried under vacuum at 60°C for 5 hours. Yield (based on PIM-1): 90.6%. GPC (in DMF): Mw = 35504 g / mol and Mw / Mn = 2.26.

[0014] Step 3, preparation of AOPIM-1 / SA aerogel, specifically includes the following steps:

[0015] First, mix 0.3g SA and 0.3g AOPIM-1 and add them to 10ml of deionized water. Stir at room temperature for 24 hours to form a homogeneous solution. Then, pour the solution into a specific container and prepare aerogel by freezing it from bottom to top with liquid nitrogen. The aerogel prepared in this way has orderly pores and is vertically oriented.

[0016] Then, freeze-drying was performed, and the sample aerogel was placed in a 5 wt% calcium chloride (CaCl2) solution to stabilize the binder structure and obtain AOPIM-1 / SA aerogel.

[0017] Step 4, Preparation of PPy-modified AOPIM-1 / SA aerogel, specifically includes the following steps:

[0018] First, dissolve 0.69 g of ammonium persulfate in 12.5 mL of deionized water to obtain solution A; dissolve 0.2 g of pyrrole in 12.5 mL of isopropanol and add 0.5 mL of phytic acid to form solution B; place these two solutions in a refrigerator until they are cooled to 0°C, and then mix solutions A and B to obtain a mixed solution.

[0019] Then, the AOPIM-1 / SA aerogel was immersed in the mixed solution and reacted at room temperature for 24 hours. After the reaction was completed, the aerogel was thoroughly washed with deionized water.

[0020] Finally, the aerogel was pre-frozen and then freeze-dried to obtain PPy-AOPIM-1 / SA.

[0021] The present invention also provides the application of the above-mentioned PPy-AOPIM-1 / SA aerogel evaporator with vertical channels in efficient desalination and wastewater desalination.

[0022] Preferably, the PPy-AOPIM-1 / SA aerogel evaporator with vertical channels is placed in a high-concentration brine solution simulating seawater and dyeing wastewater as polluted water bodies, and then exposed to sunlight.

[0023] The beneficial effects of this invention are as follows:

[0024] This invention functionalizes PIM-1 by introducing an aminooxime group (AO), forming AOPIM-1 with an amphoteric structure, enhancing its hydrophilicity and salt resistance. Subsequently, sodium alginate is doped to prepare a vertically oriented pore aerogel, PPy-AOPIM-1 / SA. Under single-day illumination, this aerogel evaporator achieved photothermal evaporation efficiencies of 91.17% and 83.67% in pure water and 20wt% NaCl solution, respectively. Furthermore, PPy-AOPIM-1 / SA also demonstrates excellent performance in wastewater purification, efficiently purifying dye wastewater and exhibiting superior purification performance in acidic and alkaline wastewater treatment, with the post-evaporation solution reaching near-neutral pH. The long-term stability and practicality of PPy-AOPIM-1 / SA in seawater desalination and polluted water purification indicate that it holds promise as a highly efficient and environmentally friendly water treatment material, providing a new solution to the global water shortage problem. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0026] Figure 1 This is a schematic diagram of the preparation process of PPy-AO-PIM-1 / SA in this invention.

[0027] Figure 2 This is a schematic diagram of the preparation process of PIM-1 and AOPIM-1 in this invention.

[0028] Figure 3 The 1H NMR spectra of PIM-1 and AOPIM-1 in this invention are shown.

[0029] Figure 4 In the image, (ad) shows digital photographs of AO-PIM-1, sodium alginate aerogel, AOPIM-1 / SA, and PPy-AOPIM-1 / SA; (a1-a2) shows SEM images of AO-PIM-1; (b1) shows an SEM image of sodium alginate aerogel; (b2, c1-2) shows SEM images of AOPIM-1 / SA; (d1) shows an SEM image of PPy-AOPIM-1 / SA; (d2) shows EDS element mapping of PPy-AOPIM-1 / SA; (e) shows EDS layered images of PPy-AOPIM-1 / SA; and (f1-3) shows the EDS spectra and atomic percentages of elements in PPy-AOPIM-1 / SA.

[0030] Figure 5In the figure, (a) shows the complete XPS spectra of PIM-1 and AO-PIM-1; (bc) shows the XPS N1s spectra of PIM-1 and AO-PIM-1; (d, e) shows the mercury intrusion / extrusion curves and pore size distribution of PPy-AOPIM-1 / SA; and (f) shows the FT-IR spectra of PIM-1, AO-PIM-1, AO-PIM-1 / SA and PPy-AOPIM-1 / SA.

[0031] Figure 6 In the figures, (a) is the absorbance spectrum of PPy-AOPIM-1 / SA; (b) is the TGA of PPy-AOPIM-1 / SA; (c) is the water absorption rate of PPy-AOPIM-1 / SA (average of three measurements); (d) is the weight change of PPy-AOPIM-1 / SA before and after water absorption; (e) is a photograph of PPy-AOPIM-1 / SA placed on a leaf; and (f) is the shrinkage characteristics of PPy-AOPIM-1 / SA.

[0032] Figure 7 In the table, (a, b) represent the surface temperatures of PPy-AOPIM-1 / SA under different solar irradiance; (c) represents the surface temperature at 1 kWm. -2 (d) Temperatures at different heights of the evaporator after 1 hour of irradiation; (e) Mass change curves of PPy-AOPIM-1 / SA and pure water under different light irradiations for 1 hour; (f) Temperatures of pure water SA, AOPIM-1 / SA, PPy-SA, and PPy-AOPIM-1 / SA at 1kW m -2 Evaporation rate and corresponding evaporation efficiency under irradiation; (f) is the evaporation rate at 1kW m -2 The evaporation efficiency and evaporation rate of PPy-AOPIM-1 / SA were tested in 10 cycles under irradiation; (g) represents the mass change of PPy-AOPIM-1 / SA in solutions with different salinity; (h) represents the evaporation efficiency and evaporation rate of PPy-AOPIM-1 / SA in solutions with different salinity; (i) represents the evaporation efficiency and evaporation rate of PPy-AOPIM-1 / SA in 20wt% NaCl for 6 h (average of three measurements over 6 g-h).

[0033] Figure 8 In the diagram, (a) shows the salt tolerance mechanism; (b) shows the Ca2+ concentration before and after evaporation using INP. 2+ K + Mg 2+ Na + Cu 2+ and Zn 2+ (c) shows the electrical resistance of artificial seawater, pure seawater, and domestic water; (d) shows the dissolution process of 1g salt particles on the surface of PPy-AOPIM-1 / SA aerogel.

[0034] Figure 9 In the middle, (ac) are the UV spectra of CR, MB, RHB and purified water; (d) is a photograph showing the UV spectra of 1 mol L... - 1 NaOH, 1 mol L -1 pH values ​​of HCl solution and corresponding water after evaporation via PPy-AOPIM-1 / SA. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1: Synthesis of PPy-AOPIM-1 / SA Aerogel Evaporator

[0037] like Figure 1 and Figure 2 As shown, the preparation method of the PPy-AOPIM-1 / SA aerogel evaporator with vertical channels provided by the present invention includes the following steps:

[0038] 1. Synthesis of PIM-1

[0039] PIM-1 was synthesized using a low-temperature method. First, TTSBI was purified by recrystallization from methanol and dichloromethane and dried overnight in a vacuum oven at 80°C. TFTPN was purified by recrystallization from methanol at 60°C, and potassium carbonate was quenched at 120°C before use. Under nitrogen atmosphere, 10.2 g of TTSBI, 6 g of TFTPN, and anhydrous DMAc (200 mL) were added to a three-necked round-bottom flask. The mixture was stirred and heated to 65°C to completely dissolve the monomers. After dissolving into a clear solution, 10 g of potassium carbonate was introduced to bring the molar ratio of TTSBI, TFTPN, and K₂CO₃ to 1:1:2.5. The reaction was then carried out at 65°C under an inert gas atmosphere for 72 hours. After the reaction was complete, the solution was cooled to room temperature and then poured into methanol. The resulting precipitate was then purified by dissolution in chloroform and further recrystallized from methanol. The resulting polymer was refluxed in distilled water overnight, filtered, and washed several times to remove residual salts. Finally, it was dried overnight in a vacuum drying oven at 100°C to obtain PIM-1 as a yellow solid.

[0040] 2. Synthesis of Amide Oxime PIM-1 Powder

[0041] 0.6 g of PIM-1 powder and 40 mL of THF were added to a three-necked round-bottom flask equipped with a condenser and a magnetic stirrer. The solution was then heated to 65 °C and maintained under an inert nitrogen atmosphere. Next, 6 mL of hydroxylamine was added dropwise to the solution using a syringe, causing the solution to become turbid and contain some precipitate. The reaction was carried out under reflux for 20 hours. After the reaction was complete, the turbid solution was cooled to room temperature and poured into excess methanol. Amide oxime PIM-1 was obtained by filtration and washed repeatedly with ethanol. A white powder was obtained and dried under vacuum at 60 °C for 5 hours. Yield (based on PIM-1): 90.6%. GPC (in DMF): Mw = 35504 g / mol and Mw / Mn = 2.26.

[0042] 3. Preparation of AOPIM-1 / SA aerogel

[0043] First, 0.3g SA and 0.3g AOPIM-1 were mixed and added to 10ml of deionized water. After stirring at room temperature for 24 hours to form a homogeneous solution, the solution was poured into a specific container and aerogel was prepared by bottom-up freezing with liquid nitrogen. The aerogel prepared in this way has ordered pores and is vertically oriented. Then, freeze-drying was performed, and the sample aerogel was placed in a 5wt% calcium chloride (CaCl2) solution to stabilize the binder structure and obtain AOPIM-1 / SA aerogel.

[0044] 4. Preparation of PPy-modified AOPIM-1 / SA aerogel

[0045] First, 0.69 g of ammonium persulfate was dissolved in 12.5 mL of deionized water to obtain solution A; 0.2 g of pyrrole was dissolved in 12.5 mL of isopropanol, and 0.5 mL of phytic acid was added to form solution B; both solutions were placed in a refrigerator until cooled to 0 °C, and solutions A and B were mixed to obtain a mixed solution; then, AOPIM-1 / SA aerogel was immersed in the mixed solution and reacted at room temperature for 24 hours. After the reaction was completed, the aerogel was thoroughly washed with deionized water; finally, the aerogel was pre-frozen and then freeze-dried to obtain PPy-AOPIM-1 / SA.

[0046] Example 2: Application of the PPy-AOPIM-1 / SA aerogel evaporator provided by the present invention

[0047] To evaluate the photothermal conversion performance of PPy-AOPIM-1 / SA, the PPy-AOPIM-1 / SA prepared in the examples was first subjected to a photothermal evaporation experiment under experimental conditions of room temperature (23±1℃) and relative humidity (10±2%), and the surface temperature of the samples was recorded using an infrared thermal imager. To further verify its thermal insulation performance, we conducted a 1kW / m 2Under illumination conditions, the temperature at different water depths was measured using an infrared thermal imager. Regarding evaporation performance, we compared different materials at 1kW / m³. 2 A comparative experiment was conducted to measure the water mass loss under irradiation. Furthermore, to further investigate the salt tolerance of PPy-AOPIM-1 / SA, we placed PPy-AOPIM-1 / SA in solutions of different salt concentrations (including artificial seawater, 5wt%, 10wt%, and 20wt% NaCl solutions) under one solar radiation (1kW / m²). -2 The surface temperature, evaporation efficiency, and rate of the material were investigated based on the mass change of the evaporated water. The evaporation performance was tested using a laboratory simulated solar experimental system. Simultaneously, the mass change of the water in the system was monitored in real time using an electronic analytical balance, and the temperature change of the material surface was monitored using an infrared camera. Ten evaporation efficiency tests were conducted on PPy-AOPIM-1 / SA under a single solar environment. To further investigate the salt resistance of PPy-AOPIM-1 / SA and its interception effect on heavy metal ions, interfacial evaporation experiments were performed; resistance measurements further verified the desalination effect of PPy-AOPIM-1 / SA. Finally, PPy-AOPIM-1 / SA was placed in different wastewater environments (including acidic, alkaline, and dye-contaminated solutions) to observe its water purification capacity.

[0048] Figure 3 The 1H NMR spectra of PIM-1 and AOPIM-1 in this invention are shown. The 1H NMR spectra reveal the structural differences between PM-1 and AO-PIM1. The -NH2 signal at 5.81 ppm and the -OH signal at 9.44 ppm clearly indicate that the cyano group has been replaced by hydroxylamine. Furthermore, the chemical shift of AO-PIM-1 at 6.1 ppm is lower than that of PIM-1 at 6.4 ppm, mainly due to the stronger electron shielding effect of the introduced amine oxime group on the hydrogen atom at the 3-position. This further verifies the successful conversion of the cyano group. The successful introduction of this group lays the foundation for improving the hydrophilicity and salt tolerance of the solar evaporator in the later stages.

[0049] like Figure 4 (ad) shows digital photographs of AO-PIM-1, sodium alginate aerogel, AOPIM-1 / SA, and PPy-AOPIM-1 / SA, displaying actual photographs of different samples, including: AO-PIM-1, sodium alginate aerogel, an aerogel combining sodium alginate and AO-PIM-1 (AOPIM-1 / SA), and a composite aerogel with polypyrrole (PPy) sprayed on the surface (PPy-AOPIM-1 / SA). These materials were characterized using scanning electron microscopy (SEM), revealing their microstructural features.

[0050] like Figure 4Images (a1-a2) are SEM images of AO-PIM-1, showing its surface morphology. The surface exhibits a rough microporous structure, significantly increasing the material's specific surface area and providing favorable conditions for light absorption and desalination. The pore size of AO-PIM-1 matches the size of salt ions, effectively blocking salt ions from entering the micropores and achieving efficient desalination.

[0051] like Figure 4 (b1-b2) are SEM images of sodium alginate aerogel, showing the sodium alginate aerogel treated by vertical freeze-drying with liquid nitrogen. Its polygonal pore structure and smooth surface are clearly visible, which is the result of the combination of the two-dimensional morphology of the aerogel and the ice crystal extrusion effect during the freeze-drying process.

[0052] like Figure 4 (c1-2) is a SEM image of AOPIM-1 / SA. After introducing AO-PIM-1, the figure shows that vertically arranged wide channels were formed during the freeze-drying process. The good combination of AO-PIM-1 and sodium alginate aerogel formed a rougher microporous structure inside and on the surface of the material. Although some pore sizes were slightly reduced, the specific surface area was increased, and the barrier effect on salt ions was enhanced, which promoted the improvement of light absorption performance.

[0053] like Figure 4 (d1) is a SEM image of PPy-AOPIM-1 / SA, showing the aerogel structure modified with polypyrrole. The modified material retains its layered porous structure, but due to the uniform adhesion of PPy particles to the inner surface of the aerogel, the surface roughness is further increased, significantly improving the photothermal conversion efficiency of the material. The combination of AO-PIM-1 and PPy optimizes the light absorption performance of the material, broadening its application prospects in solar evaporation systems.

[0054] like Figure 4 (d2) is the EDS element mapping for PPy-AOPIM-1 / SA.

[0055] like Figure 4 (e) is an EDS layered image of PPy-AOPIM-1 / SA, combined with energy dispersive spectroscopy (EDS) elemental analysis. Figure 4 The images (e, d2) clearly show the presence of carbon (C), nitrogen (N), and oxygen (O) elements, originating from PPy and AO-PIM-1 respectively, indicating their successful integration. Through surface modification and composite processing, the structure and properties of the PPy-AOPIM-1 / SA material were significantly optimized, enhancing its overall performance in photothermal conversion and desalination processes, demonstrating its broad application potential in solar-driven water treatment.

[0056] like Figure 4EDS spectra and atomic percentages of elements in (f1-3)PPy-AOPIM-1 / SA.

[0057] like Figure 5 (a) shows the complete XPS spectra of PIM-1 and AO-PIM-1. XPS analysis reveals the elemental composition and nitrogen state of PIM-1 and its derivatives. Figure 5 In the N1s high-resolution spectrum of b, the N1s peak of PIM-1 appears at 399.0 eV, indicating the presence of nitrile groups.

[0058] like Figure 5 (bc) shows the XPS N 1s spectra of PIM-1 and AO-PIM-1. The figure shows that in the N 1s peak of AO-PIM-1 (… Figure 5 c) The peak split into two subpeaks, corresponding to C=N-OH (399.6 eV) and C-NH2 (398.9 eV), respectively, reflecting the successful introduction of the amine oxime group and the change in the PIM-1 structure. These results further validate the effective modification of the PIM-1 structure and the introduction of new groups.

[0059] like Figure 5 (d, e) show the mercury porosimetry / extrusion curves and pore size distribution of PPy-AOPIM-1 / SA. The pore size distribution of the aerogel was measured using mercury porosimetry, and the results show that the pore size is mainly concentrated between 0 and 50 micrometers, indicating that the material consists of micropores and mesopores. The measured total pore area is 2.58 m². 2 With a porosity of 54.85% and a density of / g, the porous nature of the aerogel is demonstrated. This porous structure helps improve the material's moisture transport performance and salt resistance, supporting its potential applications in water treatment and humidity control.

[0060] like Figure 5 (f) shows the FT-IR spectra of PIM-1, AO-PIM-1, AO-PIM-1 / SA, and PPy-AOPIM-1 / SA, demonstrating further verification of these structural changes by Fourier transform infrared spectroscopy (FTIR). The disappearance of the nitrile group (-CN) peak at 2240 cm⁻¹ in PIM-1 indicates complete conversion of the nitrile group; while at 1660 cm⁻¹... -1 The strong peak at 915cm -1 The weak peaks at these locations correspond to the stretching vibrations of C=N and NO, respectively, confirming the formation of the amine oxime group. In AO-PIM-1, the peaks at 3000-3700 cm⁻¹... -1 The broadband peak within the range corresponds to the antisymmetric peak of NH2 (3482 cm⁻¹). -1 ) and symmetry (3340cm) -1The stretching vibration further confirmed the successful synthesis of the AO-PIM-1. After mixing AO-PIM-1 with sodium alginate (SA), the infrared spectrum was observed in the range of 3488-3100 cm⁻¹. -1 Signals of NH and OH bonds appeared within the range, and at 919 cm⁻¹ -1 The NO bond peak at 1562 cm⁻¹ indicates that AO-PIM-1 has successfully bonded to SA. The formation of these NH and OH bonds suggests hydrogen bonding interactions between the two, and the introduction of hydrogen bonds contributes to enhancing the mechanical strength of the composite material. Meanwhile, in the polypyrrole-modified PPy-AO-PIM-1 / SA composite aerogel, the FTIR spectrum at 1562 cm⁻¹... -1 and 1629cm -1 The appearance of symmetrical and asymmetrical vibration peaks of the pyrrole ring further confirms the successful modification of polypyrrole and enhances the light absorption performance of the composite material.

[0061] like Figure 6 (a) shows the absorbance spectrum of PPy-AOPIM-1 / SA, illustrating its UV-Vis-NIR absorption spectrum, indicating a light absorption rate exceeding 93%. The introduction of PPy enhances the multiple scattering effect on the material surface, thereby improving light absorption performance and generating a thermal localization effect on the material surface. This provides strong evidence for the efficient application of PPy-AOPIM-1 / SA in photothermal conversion.

[0062] like Figure 6 (b) For the TGA of PPy-AOPIM-1 / SA, the mass loss of the aerogel is only 10.04% in the range of 0-206℃, indicating its excellent stability within this temperature range, and the effect of absorbed moisture from the environment on mass change is negligible. The aerogel begins to decompose in the range of 206-484℃, with a mass loss reaching 28.74%. In the third stage (484-800℃), the material experiences a further mass loss of 17.82%. Overall analysis shows that the aerogel exhibits good stability at high temperatures, making it less susceptible to damage in long-term outdoor applications such as solar evaporation. Considering that the surface temperature of solar absorbers is typically below 100℃, this thermal stability offers potential prospects for the practical application of aerogels.

[0063] like Figure 6 (c) shows the water absorption rate of PPy-AOPIM-1 / SA (average of three measurements), demonstrating the rapid water absorption capacity of PPy-AOPIM-1 / SA. Water completely penetrates into the aerogel within 12 seconds, indicating its strong water transport performance. This rapid water absorption characteristic enhances its application potential in water treatment and interfacial evaporation.

[0064] like Figure 6 (d) shows the weight change of PPy-AOPIM-1 / SA before and after water absorption. Since water absorption capacity directly affects its evaporation efficiency, the figure shows that the weight of the aerogel in the dry state is 0.8323 g, and the weight increases to 7.3849 g after water absorption, which is 8.8 times its own weight. This significant water absorption capacity ensures that the material can continuously provide moisture during the interfacial evaporation process, thereby maintaining good evaporation efficiency.

[0065] like Figure 6 (e) A photograph of PPy-AOPIM-1 / SA placed on a leaf, as shown in the figure. The aerogel has an extremely low weight (0.31 g / cm³). 3 It is so light that it can be placed on a leaf and maintains good support even in humid environments.

[0066] like Figure 6 (f) shows the shrinkage characteristics of PPy-AOPIM-1 / SA. As shown in the figure, the diameter of the aerogel in the dry state is 15.0 mm, while after soaking in water for 20 minutes, its diameter expands to approximately 25.0 mm, exhibiting significant shrinkage and expansion capabilities. This characteristic indicates its strong adaptability to aquatic environments.

[0067] like Figure 7 (a, b) represent the surface temperatures of PPy-AOPIM-1 / SA under different solar irradiances, at 1kW / m 2 Under irradiation, the surface temperature of PPy-AOPIM-1 / SA rapidly rose to 32.7°C within just 5 minutes, then continued to rise to 39.1°C and remained stable, with a maximum temperature of 41.6°C within 1 hour. At 2kW / m² 2 and 3kW / m 2 Under irradiation, the highest temperatures of PPy-AOPIM-1 / SA were 48.2℃ and 57.2℃, respectively.

[0068] like Figure 7 (c) is 1kW m -2 The temperature at different heights of the evaporator after 1 hour of irradiation showed that the temperature decreased significantly with increasing water depth. This indicates that PPy-AOPIM-1 / SA can effectively block heat conduction to the lower water layers and has a good heat insulation effect.

[0069] like Figure 7 (d) shows the mass change curves of PPy-AOPIM-1 / SA and pure water under different light irradiation for 1 hour;

[0070] like Figure 7(e) shows the evaporation rates and corresponding evaporation efficiencies of pure water SA, AOPIM-1 / SA, PPy-SA, and PPy-AOPIM-1 / SA under 1kW m⁻² irradiation. The evaporation rate of PPy-AOPIM-1 / SA is 1.54 kg / m². 2 •h, significantly higher than pure water (0.51kg / m 2 ·h), PPy-SA (1.49kg / m 2 ·h) and AOPIM-1 / SA (1.30kg / m 2 ·h).

[0071] like Figure 7 (f) represents the 1kW m -2 Under irradiation, the evaporation efficiency and evaporation rate of PPy-AOPIM-1 / SA were tested in 10 cycles. The evaporation performance of PPy-AOPIM-1 / SA remained stable in the 10 cycles. The efficiency and rate values ​​of the cycles did not change and the appearance of the samples remained unchanged, which proved its excellent cycle stability.

[0072] like Figure 7 (g,h) represents the mass change, evaporation efficiency, and evaporation rate of PPy-AOPIM-1 / SA in solutions with different salinity. PPy-AOPIM-1 / SA still exhibits stable evaporation rates in these salt solutions of different concentrations, which are 1.50, 1.47, 1.44, and 1.40 kg / m³, respectively. 2 The corresponding evaporation efficiencies are 89%, 88%, 86%, and 83%, respectively, for h.

[0073] like Figure 7 (i) Evaporation efficiency and evaporation rate of PPy-AOPIM-1 / SA in 20wt% NaCl for 6 h (average of three measurements over 6 g-h).

[0074] like Figure 8 (a) shows the salt tolerance mechanism. The PPy-AOPIM-1 / SA aerogel has a porous structure with oriented vertical alignment. Simultaneously, the synergistic effect of the microporous structure of AO-PIM-1 and the amine oxime groups creates a seawater concentration gradient within the aerogel, with the upper layer having a higher concentration than the lower layer, thus forming a dynamic equilibrium dilution effect within the aerogel. Therefore, this photothermal evaporator exhibits a high evaporation rate in seawater of varying concentrations.

[0075] like Figure 8 (b) Ca before and after evaporation using INP 2+ K + Mg 2+ Na + Cu 2+ and Zn 2+The concentration of the main ions (such as Na+) in artificial seawater before and after interfacial evaporation. + Mg 2+ K + Ca 2+ The concentration of ions was significantly reduced. Inductively coupled plasma (ICP) testing showed that the concentrations of all ions in the water sample after evaporation met the standards of the World Health Organization (WHO). Furthermore, PPy-AOPIM-1 / SA significantly reduced the concentration of heavy metal ions (such as Cu). 2+ Zn 2+ The interception effect is excellent, with an interception rate of over 99%.

[0076] like Figure 8 (c) Resistance values ​​were tested for artificial seawater, purified seawater, and domestic water. The resistance of artificial seawater was 61.4 kΩ, while the resistance of the treated water was as high as 1.3 MΩ, similar to that of domestic water (1.1 MΩ). This indicates that the material not only has a good desalination effect in seawater desalination but also provides broad application prospects for domestic water treatment.

[0077] like Figure 8 (d) is an image of the dissolution process of 1g salt particles on the surface of PPy-AOPIM-1 / SA aerogel. PPy-AOPIM-1 / SA can quickly dissolve salt particles due to its excellent pore structure. Although the dissolution time is slightly prolonged due to the uneven distribution of salt particles, the salt can be quickly dissolved after a short period of deposition in the pores.

[0078] like Figure 9 The UV spectra of CR, MB, RHB and purified water are shown in (ac). The dye-contaminated solution became colorless after purification, and the characteristic absorption peaks of CR, MB and RhB completely disappeared at 498 nm, 660 nm and 552 nm, respectively, further demonstrating the excellent ability of PPy-AOPIM-1 / SA in the purification of organic dyes.

[0079] like Figure 9 (d) shows the photograph of 1 mol L -1 NaOH, 1 mol L -1 The pH values ​​of HCl solution and corresponding water after evaporation by PPy-AOPIM-1 / SA were measured. Experimental results show that PPy-AOPIM-1 / SA also exhibits good purification performance in 1 mol / L acid and alkali solutions. The pH values ​​of the evaporated acid and alkali solutions are close to 7, indicating that this material can effectively neutralize and purify high-concentration acid and alkali solutions, demonstrating excellent acid and alkali wastewater treatment capabilities. Furthermore, the evaporation rate of the PPy-AOPIM-1 / SA evaporator in solutions containing anionic dyes such as Congo Red (CR), Rhodamine B (RhB), and cationic dyes such as Methylene Blue (MB) is close to that of pure water, indicating its promising application prospects in practical wastewater purification.

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels, characterized in that, Includes the following steps: Step 1: Synthesis of PIM-1; Step 2: Synthesis of amide oxime PIM-1 powder; Step 3: Preparation of AOPIM-1 / SA aerogel; Step 4: Preparation of PPy-modified AO-PIM-1 / SA aerogel.

2. The method for preparing a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels according to claim 1, characterized in that, In step one, PIM-1 is synthesized using a low-temperature method, specifically including the following steps: First, TTSBI was purified by recrystallization from methanol and dichloromethane and dried overnight in a vacuum oven at 80°C. TFTPN was purified by recrystallization from methanol at 60°C and quenched with potassium carbonate at 120°C before use. Under nitrogen atmosphere, 10.2 g of TTSBI, 6 g of TFTPN, and 200 mL of anhydrous DMAc were added to a three-necked round-bottom flask. The mixture was stirred and heated to 65°C to completely dissolve the monomers. After dissolving into a clear solution, 10 g of K2CO3 was introduced into the solution to make the molar ratio of TTSBI, TFTPN, and K2CO3 1:1:2.

5. The reaction was carried out at 65°C under inert gas atmosphere for 72 hours. After the reaction was completed, the solution was cooled to room temperature and then poured into methanol. The resulting precipitate was then purified by dissolving it in chloroform and further recrystallized with methanol. The resulting polymer was refluxed in distilled water overnight, then filtered and washed several times to remove residual salts. Finally, it was dried overnight in a vacuum drying oven at 100°C to obtain PIM-1 as a yellow solid.

3. The method for preparing a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels according to claim 2, characterized in that, In step two, the synthesis steps of the amide oxime PIM-1 powder are as follows: First, add 0.6 g of PIM-1 powder and 40 mL of THF to a three-necked round-bottom flask equipped with a condenser and a magnetic stirrer, and heat the solution to 65°C and maintain it in an inert nitrogen atmosphere. Then, using a syringe, 6 ml of hydroxylamine was added dropwise to the solution, causing the solution to become cloudy and contain some precipitate. The reaction was carried out under reflux for 20 hours. Finally, after the reaction was complete, the turbid solution was cooled to room temperature and poured into excess methanol. AOPIM-1 was separated by filtration and washed multiple times with ethanol to obtain an off-white powder, which was then dried under vacuum at 60°C for 5 hours.

4. The method for preparing a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels according to claim 3, characterized in that, In step three, the preparation steps of AOPIM-1 / SA aerogel are as follows: First, mix 0.3g SA and 0.3g AOPIM-1 and add them to 10ml deionized water. Stir at room temperature for 24 hours to form a homogeneous solution. Then, pour the solution into a specific container and prepare aerogel by freezing it from bottom to top with liquid nitrogen. The aerogel prepared in this way has orderly pores and is vertically oriented. Then, freeze-drying was performed, and the sample aerogel was placed in a 5wt% calcium chloride (CaCl2) solution to stabilize the binder structure and obtain AOPIM-1 / SA aerogel.

5. The method for preparing a PPy-AOPIM-1 / SA aerogel evaporator with vertical channels according to claim 4, characterized in that, The preparation of PPy-modified AO-PIM-1 / SA aerogel includes the following steps: First, dissolve 0.69 g of ammonium persulfate in 12.5 mL of deionized water to obtain solution A; dissolve 0.2 g of pyrrole in 12.5 mL of isopropanol and add 0.5 mL of phytic acid to form solution B; Place both solutions in a refrigerator until they cool to 0°C to obtain a mixed solution from solution A and solution B. Then, the AOPIM-1 / SA aerogel was immersed in the mixed solution and reacted at room temperature for 24 hours. After the reaction was completed, the aerogel was thoroughly washed with deionized water. Finally, the aerogel was pre-frozen and then freeze-dried to obtain PPy-AOPIM-1 / SA.

6. The PPy-AOPIM-1 / SA aerogel evaporator with vertical channels prepared by the method according to claim 1.

7. The application of the PPy-AOPIM-1 / SA aerogel evaporator with vertical channels as described in claim 6 in efficient desalination and wastewater purification.

8. The application according to claim 7, characterized in that: The PPy-AOPIM-1 / SA aerogel evaporator with vertical channels is placed in a high-concentration salt water environment simulating seawater and dyeing wastewater as polluted water bodies, and then exposed to sunlight.

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